The english Netscape (dunno for other mailers) 
can't display japanese text when writing an email. 
It will only display those dots. But as long as 
you selected the japanese character set, the email 
should be ok. (and if you send it to yourself, 
Netscape should be able to display it as long as 
you have a japanese font installed on your 
system).

Cheers,
Yann Stettler